|Publication number||US7398592 B2|
|Application number||US 11/093,962|
|Publication date||Jul 15, 2008|
|Filing date||Mar 29, 2005|
|Priority date||Mar 29, 2005|
|Also published as||US20060225268|
|Publication number||093962, 11093962, US 7398592 B2, US 7398592B2, US-B2-7398592, US7398592 B2, US7398592B2|
|Inventors||Quang Le, Jui-Lung Li|
|Original Assignee||Hitachi Global Storage Technologies Netherlands, B.V.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (3), Classifications (25), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates generally to magnetic heads that are utilized with thin film hard disk data storage devices, and more particularly to the design and fabrication of a write pole for a perpendicular magnetic head.
2. Description of the Prior Art
Hard disk drives generally include one or more rotatable data storage disks having a magnetic data storage layer formed thereon. Data in the form of small magnetized areas, termed magnetic data bits, are written onto the magnetic layers of the disks by a magnetic head that includes magnetic poles through which magnetic flux is caused to flow. Magnetic flux flowing from a pole tip portion of the magnetic poles in close proximity to the magnetic layer on the disk, causes the formation of the magnetic bits within the magnetic layer.
In recent years, perpendicular magnetic heads have received renewed interest in the effort to extend data areal storage density. The increased demand for higher areal storage density has correspondingly fueled the exploration of a robust process to form the write pole of the perpendicular magnetic head. Current exploratory fabrication methods use an ion milling process to fabricate the write pole, in which a photolithographical pattern is image-transferred by reactive ion etching (RIE) into a material with a low ion milling rate using a bi-layer or tri-layer hard mask scheme. The hard mask then functions as a transfer mask to pattern the write pole into a full-film magnetic material. Since patterning is by a physical process, one major complication in developing a robust write pole fabrication process is the difficulty in removing mask overburden materials and flattening the surface of the wafer without damaging the write pole. As the dimensions of the write pole shrink and the requirements on the retention of the write pole thickness, width and shape become more stringent, a major challenge is to develop a manufacturable process that overcomes the inherent within wafer non-uniformity that often accompanies the conventional CMP process.
This invention includes a manufacturable method, including a CMP liftoff process, for removing masking materials after ion milling for fabricating the write pole of a magnetic head. Significant parameters for the CMP assisted liftoff process include the thickness of the remaining mask materials after the write pole ion milling for effective CMP assisted liftoff, the thickness of the dielectric fill material deposited to protect the write pole during the CMP liftoff step, and the type of CMP slurry, polishing pad and the polishing conditions that are required to yield satisfactory results.
It is an advantage of the method for fabricating a magnetic pole of the present invention that a well shaped magnetic pole is more reliably formed within magnetic heads that are fabricated across the surface of a wafer substrate.
It is another advantage of the process of fabricating a magnetic pole of the present invention that magnetic poles having a straight trailing edge and sharp, well-defined corners are more reliably formed across the surface of a wafer substrate.
It is a further advantage of the method for fabricating a magnetic pole of the present invention that remaining portions of an ion milling mask are removed from the magnetic pole using a CMP liftoff step.
It is yet another advantage of the method for fabricating a magnetic pole of the present invention that a fill layer is deposited to protect the magnetic pole prior to a CMP liftoff step that removes remaining ion milling mask material from the magnetic pole.
It is yet a further advantage of the method for fabricating a magnetic pole of the present invention that a diamond-like-carbon (DLC) layer is deposited upon a fill layer to protect the fill layer and magnetic pole during a CMP liftoff step that removes remaining ion milling mask material from the magnetic pole.
These and other features and advantages of the present invention will no doubt become apparent to those skilled in the art upon reading the following detailed description which makes reference to the several figures of the drawing.
The following drawings are not made to scale as an actual device, and are provided for illustration of the invention described herein.
The magnetic head of the present invention is utilized to read and write data to magnetic media, such as a hard disk in a hard disk drive. A simplified top plan view of a hard disk drive 10 is presented in
The perpendicular head 38 includes a first magnetic shield layer (S1) 60 that is formed upon the upper surface 68 of the slider substrate 72. A first insulation layer (G1) 76 is formed on the S1 shield 60 and a read head sensor element 80 is formed on the G1 layer 76. A second insulation layer (G2) 84 is formed on the sensor 80 and a second magnetic shield layer (S2) 88 is formed upon the G2 insulation layer 84. An electrical insulation layer 92 is then deposited upon the S2 shield 88, and a first magnetic pole (P1) 96 is fabricated upon the insulation layer 92. An induction coil structure 100 is fabricated upon the P1 pole 96, that includes induction coil turns 104 that are typically formed upon an electrical insulation layer 108 and within filling insulation 112. A second magnetic pole layer 120, typically termed a shaping layer 120, is fabricated on top of the induction coil structure 100. A magnetic back gap piece 128 joins the back portions of the P1 pole 96 and the shaping layer 120, such that magnetic flux can flow between them. A write pole probe layer 140 including a write pole tip 148 is next fabricated in magnetic flux communication with the shaping layer 120.
As can be seen in the top plan view of the probe layer presented in
Following the fabrication of the probe layer 140, further magnetic head fabrication steps, such as the fabrication of electrical interconnects (not shown), are accomplished, as are well known to those skilled in the art, and the magnetic head is subsequently encapsulated, such as with the deposition of an alumina layer 160. Thereafter, the wafer is sliced into rows of magnetic heads, and the ABS surface 42 of the heads is carefully polished and lapped and the discrete magnetic heads 38 are ultimately formed.
As is well understood by those skilled in the art, electrical current flowing through the induction coil 104 will cause magnetic flux to flow through the magnetic poles of the head, where the direction of magnetic flux flow depends upon the direction of the electrical current through the induction coil. For instance, current in one direction will cause magnetic flux to flow through the shaping layer 120 through the probe layer 140 to the narrow pole tip 148 into the high coercivity magnetic layer 50 of the hard disk 12. This magnetic flux causes magnetized data bits to be recorded in the high coercivity layer 50 as the disk moves past the magnetic head in direction 56, where the magnetization of the data bits is perpendicular to the surface 19 of the disk 12. It is of particular significance to the present invention that the trailing edge 158 of the pole tip 148 plays a substantial role in determining the shape and magnetic properties of the magnetic data bits that are formed within the disk, and
As is next depicted in
Thereafter, as is depicted in
A standard ion milling step using a species such as argon is next employed to remove the unmasked probe layer material 204 from the surface of the wafer. Most, though not all, of the remaining masking materials are also removed in this ion milling step. Thereafter, as is seen in the cross-sectional view of
It is now necessary to remove the remaining portion of the first Duramide layer 212 and first DLC layer 208 that remain on top of the probe layer 204 as seen in
As is next depicted in the cross-sectional view of
A very mild chemical mechanical polishing (CMP) liftoff step is next undertaken to remove the remaining milling mask material 212 and fences 260 (see
In order to achieve complete CMP liftoff and maintain the integrity of the pole shape it is important to use an appropriate type of CMP slurry and a set of mild polishing conditions. Mildly alkaline pH slurries (pH from approximately 9 to 11 and preferably approximately 10) with silica or alumina abrasive particles having a mean particle size of from approximately 0.02 to 0.15 um and preferably approximately 0.05 um or less are desirable for this application. Hard polishing pads such as polyurethane-based pads are preferably used to avoid aggressive deformation of the pad and damage to the pole surface. In addition, the polishing pressure should be kept in a range of approximately 2 psi to 4 psi and preferably approximately 3 psi or lower to avoid aggressive polishing of the dielectric/alumina and the possibility of damaging the pole; the material removal rate with these conditions is approximately 200 Å to 400 Å. per minute.
After the CMP liftoff step, a reactive ion etch step is next conducted utilizing oxygen reactive ion species to remove the first and second DLC layers, 208 and 274 respectively. As depicted in
Thereafter, as depicted in
As indicated hereabove, accurate measurement and control of the thickness of the fill material 270 is important in achieving the results of the present invention. Specifically,
As set forth in detail above, the present invention includes a manufacturable method for removing mask overburden and re-deposition fence materials after the probe layer ion milling for wafer level fabrication of the write pole of perpendicular magnetic heads. It includes a CMP assisted liftoff process, with significant parameters that include the thickness of the resist/organic mask materials desired on the pole after ion milling for effective CMP assisted liftoff, the thickness of the dielectric fill material needed to protect the write pole during the CMP liftoff step, and the type of CMP slurry, polishing pad and polishing conditions necessary to yield satisfactory results.
While the present invention has been shown and described with regard to certain preferred embodiments, it is to be understood that modifications in form and detail will no doubt be developed by those skilled in the art upon reviewing this disclosure. It is therefore intended that the following claims cover all such alterations and modifications that nevertheless include the true spirit and scope of the inventive features of the present invention.
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|US6757143||Mar 26, 2002||Jun 29, 2004||Kabushiki Kaisha Toshiba||Magnetoresistive effect element, its manufacturing method, magnetic head, magnetic reproducing apparatus, and magnetic memory|
|US7255784 *||Oct 27, 2003||Aug 14, 2007||Sony Corporation||Polishing method and electropolishing apparatus|
|US20020027751||Jul 9, 2001||Mar 7, 2002||Koji Shimazawa||Magnetoresistive effect thin-film magnetic head and manufacturing method of magnetoresistive effect thin-film magnetic head|
|US20030235989||Feb 10, 2003||Dec 25, 2003||Seagate Technology Llc||Process for CMP assisted liftoff|
|US20040071017||Jun 18, 2003||Apr 15, 2004||Seagate Technology Llc||Disc drive having electromagnetic biased shieldless CPP reader|
|US20040106295||Nov 29, 2002||Jun 3, 2004||Marie-Claire Cyrille||CMP assisted liftoff micropatterning|
|US20060101636 *||Nov 18, 2004||May 18, 2006||Hitachi Global Storage Technologies||Method for patterning a magnetoresistive sensor|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8796152||Dec 13, 2012||Aug 5, 2014||HGST Netherlands B.V.||Method for manufacturing a magnetoresistive sensor|
|US9053735||Jun 20, 2014||Jun 9, 2015||Western Digital (Fremont), Llc||Method for fabricating a magnetic writer using a full-film metal planarization|
|WO2015157479A3 *||Apr 9, 2015||Dec 3, 2015||S&C Electric Company||Enclosure with integrated locking system|
|U.S. Classification||29/603.16, 29/603.18, 360/319, 204/192.34, 29/603.15, 29/603.13, 360/122, 205/122, 205/119, 29/603.14, G9B/33.013, 451/41, 204/192.1, 360/317, 451/5|
|International Classification||G11B5/127, H04R31/00|
|Cooperative Classification||Y10T29/49041, Y10T29/49046, Y10T29/49048, Y10T29/49043, G11B33/0438, Y10T29/49052, Y10T29/49044|
|Mar 29, 2005||AS||Assignment|
Owner name: HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LE, QUANG;LI, JUI-LUNG;REEL/FRAME:016436/0470;SIGNING DATES FROM 20050323 TO 20050324
|Feb 27, 2012||REMI||Maintenance fee reminder mailed|
|Jul 15, 2012||LAPS||Lapse for failure to pay maintenance fees|
|Sep 4, 2012||FP||Expired due to failure to pay maintenance fee|
Effective date: 20120715